Solid polymeric products for minimizing sprinkler wheel track ruts

ABSTRACT

Wheel track ruts form under moving sprinklers and the depth of ruts is reduced and water infiltration is increased by using solid polymeric products. Solid polymeric products containing water soluble polymer are located over each wheel track. Sprinkler water contacts and dissolves the solid polymeric products, carrying water soluble polymer into the wheel track.

CROSS-REFERENCE TO RELATED APPLICATIONS

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STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

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REFERENCE TO SEQUENCE LISTING, A TABLE OR A COMPUTER PROGRAM LISTINGCOMPACT DISK APPENDIX

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BACKGROUND OF THE INVENTION

The primary purpose for development of this invention is to provide acost effective method of minimizing agricultural sprinkler wheel trackruts. It relates to stabilizing soil structure with water solublepolymer. Center-pivot sprinklers and linear movement sprinklers uselarge wheels to enable movement through an irrigated field. There aregenerally one or more support towers on these sprinkler systems. Eachtower generally has two tires, one trailing the other. Due to the weightof the overhead sprinkler system and the softness of the wet ground thewheel tracks can become deep ruts, occasionally causing the sprinklersystem to get stuck.

In the past, irrigators learned to live with the problem. They wouldpurchase special wheels (see U.S. Pat. No. 5,046,785) to prevent themfrom getting stuck in the deep ruts, or they would fill in the rutsduring the irrigation season (see U.S. Pat. Nos. 6,386,792 and4,909,334). Another option has been to move the sprinkler heads behindthe trailing wheel (see U.S. Pat. No. 6,116,527), allowing the wheels totravel on drier ground.

Irrigators have begun using water soluble polymers for soilstabilization. Until now, they have generally been applied to irrigationwater for erosion control and to improve water penetration. Liquidpolymers are being injected into sprinkler irrigations systems (see U.S.Pat. No. 6,000,625) to stabilize soil structure and improve waterpenetration. While this method begins to stabilize soil throughout thefield, it does not provide enough water soluble polymer in the wheeltracks to reduce rutting. Also, from a cost perspective, water solublepolymer is spread over the entire field instead of only in the wheeltracks.

Granular and solid polymeric products (i.e. blocks, tablets, or gellogs) have been placed in furrows for erosion control and for improvingwater infiltration during gravity irrigation (see U.S. Pat. No.5,749,672). However, prior to this invention, solid polymeric productshad not been developed or used for stabilizing sprinkler wheel tracks.

BRIEF SUMMARY OF THE INVENTION

This invention consists of solid polymeric products traveling with thesprinkler, releasing water soluble polymer into the wheel tracks as theydissolve. The preferred embodiment uses anionic polyacrylamide withcharge density ranging from low to high and molecular weights rangingfrom medium to very high. However, cationic or nonionic polyacrylamideproducts with varying charge densities and with molecular weightsvarying from low to very high may be used with some degree of success.

The solid polymeric products should be located directly over the wheeltrack or incorporate the use of a mechanism to direct the dissolvedpolymer flow into the wheel track. The solid polymeric products musthave water flowing onto them to allow the dissolution process to takeplace. These solid polymeric products should be made with a rope orother hanging device to hang them. Or, they should be placed in a porouscontainer (i.e. wire cage, porous sack, or net) and attached the centerpivot with or without a hanging device.

Depending upon the water temperature and irrigation practices, thepolymeric products may need to be reapplied during the growing season.When the solid polymeric products and dissolved, more polymeric productsshould be added. The preferred embodiment indicates refilling each sackor container with the amount initially recommended or determined to besuccessful. Alternatively, a lesser amount of polymeric products may beused for refilling later in the irrigation season.

This invention is much less expensive and more effective than previousmethods used to control rut depth or keep sprinklers from getting stuck.As an example, special tires or tire covers are very expensive and theydo not always produce the desired results. This invention is less than5% of the cost and is very effective. Injecting water soluble polymerinto the sprinkler system costs 5 to 10 times more than the cost of thisinvention and does an inadequate job of controlling wheel track ruts.This invention works very well for controlling wheel track ruts.

This invention reduces wheel track erosion, stabilizes the wheel trackagainst deep ruts due to the weight of the sprinkler system, and helpsreduce the amount of standing water in the wheel track. By removingstanding in the wheel tracks, the ground in the wheel track is drierduring each sprinkler application. Moving across drier grounddramatically reduces rutting potential.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

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DETAILED DESCRIPTION OF THE INVENTION

This invention is intended to be attached to center pivot irrigationsystems and linear movement irrigation systems. In the preferredembodiment, approximately one pound of active water soluble polymer(preferably very high molecular weight anionic polyacrylamide with acharge density between 5% and 35%) is used to treat 3,000 linear feet ofwheel track length. This number may range from less than 1000 feet toover 10,000 feet per pound of active water soluble polymer dependingupon desired results, water flow, droplet size, soil type, and length oftreatment period desired.

In a preferred embodiment, water soluble solid polymeric productscontaining polyacrylamide are placed directly over the wheel tracks andin good sprinkler water flow. The preferred embodiment includes solidpolymeric products placed in a porous sack. The sack should not inhibitwater flow to the solid polymeric products, should allow for drainageinto the wheel track below, and should hold the solid polymeric productsin place. The sack should be hung from the sprinkler system frame in thelocation described above. In the preferred embodiment, the sack hangsfrom the cross member or from the motor on the sprinkler tower.

The preferred embodiment includes a short rope attaching the sack to apart of the frame near the ground to minimize sack movement caused bywind. Keeping the bottom of the sack less than 12 inches from the groundwill minimize the potential of the polymer stream blowing to locationsoutside of the wheel track.

For the greatest benefit, these polymeric products should be appliedduring the first irrigation of the season. If applied later in theseason, ruts may have already begun to form. There may still beadvantages to using this invention later in the season, but the benefitswill not be as great.

1. A method of applying water soluble polymer to sprinkler wheel tracksin which solid polymeric products are attached to the outside of amoving sprinkler system and travel with the moving sprinkler system andin which sprinkler water leaving the sprinkler dissolves and activatesthe solid polymeric products, continuously dribbling liquid polymersolution along the length of the wheel tracks.
 2. A method according toclaim 1 in which the solid polymeric product is one or more blocksconsisting of water soluble polymer in a water soluble or waterdispersible wax matrix.
 3. A method according to claim 1 in which thesolid polymeric product is one or more tablets (or other molded shapes)consisting of water soluble polymer pressed together with otherconstituents, some of which help hold the tablets together or aid in thedissolution process.
 4. A method according to claim 1 in which the solidpolymeric product is in gel form.
 5. A method according to claim 1 inwhich the solid polymeric products are suspended by a rope or otherhanging device that is pressed or molded into or around the solidpolymeric product.
 6. A method according to claim 1 in which the solidpolymeric products are placed in a porous sack or net and directly tiedto or hung from the sprinkler, or attached to the sprinkler with a ropeor other hanging device.
 7. A method according to claim 1 in which thesolid polymeric products are placed in wire (or other material ofconstruction) cages mounted to the sprinkler or suspended with a hangingdevice.
 8. A method according to claim 1 in which the solid polymericproducts are suspended from or attached to an exterior support systemfixed to the sprinkler frame.
 9. A method according to claim 1 in whichthe solid polymeric products are located directly over the sprinklertrack.
 10. A method according to claim 1 in which the solid polymericproducts are not located directly over the sprinkler track and thedissolved polymer solution flows to the wheel track in a trough, pipe orsimilar flow delivery device.
 11. A method according to claim 1 in whichwater comes from sprinkler nozzles to dissolve the solid polymericproducts.
 12. A method according to claim 1 in which tubes or pipesdeliver water to dissolve the solid polymeric products.